In recent years, portable type electronic devices, such as portable telephones, notebook computers, personal digital assistants, and the like, are being widely used. Low voltage-type circuit devices, which are driven by a low voltage such as 3 Volts, have been employed to minimize current consumption of portable electronic devices and to make batteries used in the portable electronic devices last for longer time.
Level shift circuits are commonly employed between a power supply and an input/output (“I/O”) portion of a microchip in portable electronic devices. Many conventional level shift circuits shift a voltage signal from a lower voltage level at the core power supply, e.g., 2.5 Volts, to a higher voltage level necessary for the I/O portion of the microchip.
With increasing performance demand on circuitry of portable electronic devices, level shift circuits are being designed to accommodate higher current demands, faster speeds, lower emission requirements, and the like.
Thus, it is with respect to these considerations and others that the present invention has been made.